Olympus E-M10 IV vs Sony A7S II
The Olympus OM-D E-M10 Mark IV and the Sony Alpha 7S II are two digital cameras that were announced, respectively, in August 2020 and September 2015. Both the E-M10 IV and the A7S II are mirrorless interchangeable lens cameras that are based on a Four Thirds (E-M10 IV) and a full frame (A7S II) sensor. The Olympus has a resolution of 20.2 megapixels, whereas the Sony provides 12 MP.
Below is an overview of the main specs of the two cameras as a starting point for the comparison.
Going beyond this snapshot of core features and characteristics, what are the differences between the Olympus OM-D E-M10 Mark IV and the Sony Alpha 7S II? Which one should you buy? Read on to find out how these two cameras compare with respect to their body size, their imaging sensors, their shooting features, their input-output connections, and their reception by expert reviewers.
The side-by-side display below illustrates the physical size and weight of the Olympus E-M10 IV and the Sony A7S II. The two cameras are presented according to their relative size. Three successive views from the front, the top, and the rear are shown. All width, height and depth dimensions are rounded to the nearest millimeter.
The E-M10 IV can be obtained in two different colors (black, silver), while the A7S II is only available in black.
If the front view area (width x height) of the cameras is taken as an aggregate measure of their size, the Sony A7S II is notably larger (19 percent) than the Olympus E-M10 IV. Moreover, the A7S II is substantially heavier (64 percent) than the E-M10 IV. It is noteworthy in this context that the A7S II is splash and dust-proof, while the E-M10 IV does not feature any corresponding weather-sealing.
The above size and weight comparisons are to some extent incomplete since they do not consider the interchangeable lenses that both of these cameras require. A larger imaging sensor will tend to go along with bigger and heavier lenses, although exceptions exist. You can compare the optics available for the two cameras in the Micro Four Thirds Lens Catalog (E-M10 IV) and the Sony FE Lens Catalog (A7S II). Mirrorless cameras, such as the two under consideration, have the additional advantage of having a short flange to focal plane distance, which makes it possible to mount many lenses from other systems onto the camera via adapters.
Concerning battery life, the E-M10 IV gets 360 shots out of its BLS-50 battery, while the A7S II can take 370 images on a single charge of its NP-FW50 power pack. The battery packs of both cameras can be charged via USB, which can be very convenient when travelling.
The table below summarizes the key physical specs of the two cameras alongside a broader set of comparators. If you would like to visualize and compare a different camera combination, you can navigate to the CAM-parator app and make your selection from a broad list of cameras there.
|1.||Olympus E-M10 IV||122 mm||84 mm||49 mm||383 g||360||n||Aug 2020||699|
|2.||Sony A7S II||127 mm||96 mm||60 mm||627 g||370||Y||Sep 2015||2,999|
|3.||Olympus E-M5 III||125 mm||85 mm||50 mm||414 g||310||Y||Oct 2019||1,199|
|4.||Olympus E-PL10||117 mm||68 mm||39 mm||380 g||350||n||Oct 2019||599|
|5.||Olympus E-PL9||117 mm||68 mm||39 mm||380 g||350||n||Feb 2018||599|
|6.||Olympus E-M10 III||122 mm||84 mm||50 mm||410 g||330||n||Aug 2017||649|
|7.||Olympus E-PL8||115 mm||67 mm||38 mm||357 g||350||n||Sep 2016||549|
|8.||Olympus PEN-F||125 mm||72 mm||37 mm||427 g||330||n||Jan 2016||1,199|
|9.||Olympus E-M10 II||120 mm||83 mm||47 mm||390 g||320||n||Aug 2015||649|
|10.||Olympus E-M10||119 mm||82 mm||46 mm||396 g||320||n||Jan 2014||699|
|11.||Olympus E-PL7||115 mm||67 mm||38 mm||357 g||350||n||Aug 2014||599|
|12.||Panasonic G100||116 mm||83 mm||54 mm||352 g||270||n||Jun 2020||649|
|13.||Sony A7S III||127 mm||97 mm||81 mm||699 g||600||Y||Jul 2020||3,499|
|14.||Sony A99 II||143 mm||104 mm||76 mm||849 g||490||Y||Sep 2016||3,199|
|15.||Sony A7R II||127 mm||96 mm||60 mm||625 g||290||Y||Jun 2015||3,199|
|16.||Sony A7 II||127 mm||96 mm||60 mm||599 g||350||Y||Nov 2014||1,999|
|17.||Sony A7S||127 mm||94 mm||48 mm||489 g||380||Y||Apr 2014||2,499|
|Notes: Measurements and pricing do not include easily detachable parts, such as add-on or interchangeable lenses or optional viewfinders.|
Any camera decision will obviously take relative prices into account. The retail prices at the time of the camera’s release place the model in the market relative to other models in the producer’s line-up and the competition. The E-M10 IV was launched at a markedly lower price (by 77 percent) than the A7S II, which puts it into a different market segment. Usually, retail prices stay at first close to the launch price, but after several months, discounts become available. Later in the product cycle and, in particular, when the replacement model is about to appear, further discounting and stock clearance sales often push the camera price considerably down. Then, after the new model is out, very good deals can frequently be found on the pre-owned market.
The imaging sensor is at the core of digital cameras and its size is one of the main determining factors of image quality. All other things equal, a large sensor will have larger individual pixel-units that offer better low-light sensitivity, wider dynamic range, and richer color-depth than smaller pixels in a sensor of the same technological generation. Furthermore, a large sensor camera will give the photographer more possibilities to use shallow depth-of-field in order to isolate a subject from the background. On the downside, larger sensors tend to be associated with larger, more expensive camera bodies and lenses.
Of the two cameras under consideration, the Olympus E-M10 IV features a Four Thirds sensor and the Sony A7S II a full frame sensor. The sensor area in the A7S II is 276 percent bigger. As a result of these sensor size differences, the cameras have a format factor of, respectively, 2.0 and 1.0. The sensor in the E-M10 IV has a native 4:3 aspect ratio, while the one in the A7S II offers a 3:2 aspect.
Despite having a smaller sensor, the Olympus E-M10 IV offers a higher resolution of 20.2 megapixels, compared with 12 MP of the Sony A7S II. This megapixels advantage comes at the cost of a higher pixel density and a smaller size of the individual pixel (with a pixel pitch of 3.34μm versus 8.40μm for the A7S II). However, it should be noted that the E-M10 IV is much more recent (by 4 years and 10 months) than the A7S II, and its sensor will have benefitted from technological advances during this time that make it possible to gather light more efficiently. Coming back to sensor resolution, it should be mentioned that the E-M10 IV has no anti-alias filter installed, so that it can capture all the detail its sensor resolves.
The resolution advantage of the Olympus E-M10 IV implies greater flexibility for cropping images or the possibility to print larger pictures. The maximum print size of the E-M10 IV for good quality output (200 dots per inch) amounts to 25.9 x 19.4 inches or 65.8 x 49.4 cm, for very good quality (250 dpi) 20.7 x 15.6 inches or 52.7 x 39.5 cm, and for excellent quality (300 dpi) 17.3 x 13 inches or 43.9 x 32.9 cm. The corresponding values for the Sony A7S II are 21.2 x 14.2 inches or 53.8 x 36 cm for good quality, 17 x 11.3 inches or 43.1 x 28.8 cm for very good quality, and 14.1 x 9.4 inches or 35.9 x 24 cm for excellent quality prints.
The Olympus OM-D E-M10 Mark IV has a native sensitivity range from ISO 200 to ISO 25600, which can be extended to ISO 100-25600. The corresponding ISO settings for the Sony Alpha 7S II are ISO 100 to ISO 102400, with the possibility to increase the ISO range to 50-409600.
Since 2007, DXO Mark has published sensor performance measurements that have been derived using a consistent methodology. This service determines an overall sensor rating, as well as sub-scores for low-light sensitivity ("DXO Sports"), dynamic range ("DXO Landscape"), and color depth ("DXO Portrait"). The adjacent table reports on the physical sensor characteristics and the outcomes of the DXO sensor quality tests for a sample of comparator-cameras.
| DXO |
|1.||Olympus E-M10 IV||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|2.||Sony A7S II||Full Frame||12.0||4240||2832||4K/30p||23.6||13.3||2993||85|
|3.||Olympus E-M5 III||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|4.||Olympus E-PL10||Four Thirds||15.9||4608||3456||4K/30p||..||..||..||..|
|5.||Olympus E-PL9||Four Thirds||15.9||4608||3456||4K/30p||..||..||..||..|
|6.||Olympus E-M10 III||Four Thirds||15.9||4608||3456||4K/30p||..||..||..||..|
|7.||Olympus E-PL8||Four Thirds||15.9||4608||3456||1080/30p||..||..||..||..|
|8.||Olympus PEN-F||Four Thirds||20.2||5184||3888||1080/60p||23.1||12.4||894||74|
|9.||Olympus E-M10 II||Four Thirds||15.9||4608||3456||1080/60p||23.1||12.5||842||73|
|10.||Olympus E-M10||Four Thirds||15.9||4608||3456||1080/30p||22.8||12.3||884||72|
|11.||Olympus E-PL7||Four Thirds||15.9||4608||3456||1080/30p||22.7||12.4||873||72|
|12.||Panasonic G100||Four Thirds||20.2||5184||3888||4K/30p||..||..||..||..|
|13.||Sony A7S III||Full Frame||12.0||4240||2832||4K/120p||23.7||13.9||2520||86|
|14.||Sony A99 II||Full Frame||42.2||7952||5304||4K/30p||25.4||13.4||2317||92|
|15.||Sony A7R II||Full Frame||42.2||7952||5304||4K/30p||26.0||13.9||3434||98|
|16.||Sony A7 II||Full Frame||24.0||6000||4000||1080/60p||24.9||13.6||2449||90|
|17.||Sony A7S||Full Frame||12.0||4240||2832||1080/60p||23.9||13.2||3702||87|
Many modern cameras are not only capable of taking still images, but can also record movies. Both cameras under consideration have a sensor with sufficiently fast read-out times for moving pictures, and both provide the same movie specifications (4K/30p).
Apart from body and sensor, cameras can and do differ across a range of features. The two cameras under review are similar with respect to both having an electronic viewfinder. However, the one in the A7S II offers a slightly higher resolution than the one in the E-M10 IV (2400k vs 2360k dots). The following table reports on some other key feature differences and similarities of the Olympus E-M10 IV, the Sony A7S II, and comparable cameras.
|1.||Olympus E-M10 IV||2360||n||3.0||1040||tilting||Y||1/4000s||15.0||Y||Y|
|2.||Sony A7S II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|3.||Olympus E-M5 III||2360||n||3.0||1040||swivel||Y||1/8000s||10.0||n||Y|
|6.||Olympus E-M10 III||2360||n||3.0||1040||tilting||Y||1/4000s||8.6||Y||Y|
|9.||Olympus E-M10 II||2360||n||3.0||1040||tilting||Y||1/4000s||8.0||Y||Y|
|13.||Sony A7S III||9440||n||3.0||1440||swivel||Y||1/8000s||10.0||n||Y|
|14.||Sony A99 II||2400||Y||3.0||1229||full-flex||n||1/8000s||12.0||n||Y|
|15.||Sony A7R II||2400||n||3.0||1229||tilting||n||1/8000s||5.0||n||Y|
|16.||Sony A7 II||2400||n||3.0||1230||tilting||n||1/8000s||5.0||n||Y|
One difference between the cameras concerns the presence of an on-board flash. The E-M10 IV has one, while the A7S II does not. While the built-in flash of the E-M10 IV is not very powerful, it can at times be useful as a fill-in light.The E-M10 IV has an articulated LCD that can be turned to be front-facing. This characteristic will be appreciated by vloggers and photographers who are interested in snapping selfies. In contrast, the A7S II does not have a selfie-screen.
The reported shutter speed information refers to the use of the mechanical shutter. Yet, some cameras only have an electronic shutter, while others have an electronic shutter in addition to a mechanical one. In fact, both cameras under consideration feature an electronic shutter, which makes completely silent shooting possible. However, this mode is less suitable for photographing moving objects (risk of rolling shutter) or shooting under artificial light sources (risk of flickering).
The Olympus E-M10 IV has an intervalometer built-in. This enables the photographer to capture time lapse sequences, such as flower blooming, a sunset or moon rise, without purchasing an external camera trigger and related software.
The E-M10 IV writes its imaging data to SDXC cards, while the A7S II uses SDXC or Memory Stick PRO Duo cards. The E-M10 IV supports UHS-II cards (Ultra High Speed data transfer of up to 312 MB/s), while the A7S II can use UHS-I cards (up to 104 MB/s).
For some imaging applications, the extent to which a camera can communicate with its environment can be an important aspect in the camera decision process. The table below provides an overview of the connectivity of the Olympus OM-D E-M10 Mark IV and Sony Alpha 7S II and, in particular, the interfaces the cameras (and selected comparators) provide for accessory control and data transfer.
| WiFi |
| NFC |
|1.||Olympus E-M10 IV||Y||stereo||mono||-||-||micro||2.0||Y||-||Y|
|2.||Sony A7S II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|3.||Olympus E-M5 III||Y||stereo||mono||Y||-||micro||2.0||Y||-||Y|
|6.||Olympus E-M10 III||Y||stereo||mono||-||-||micro||2.0||Y||-||-|
|9.||Olympus E-M10 II||Y||stereo||mono||-||-||micro||2.0||Y||-||-|
|13.||Sony A7S III||Y||stereo||mono||Y||Y||full||3.2||Y||-||Y|
|14.||Sony A99 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||Y|
|15.||Sony A7R II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
|16.||Sony A7 II||Y||stereo||mono||Y||Y||micro||2.0||Y||Y||-|
It is notable that the A7S II has a headphone jack, which makes it possible to attach external headphones and monitor the quality of sound during the recording process. The E-M10 IV lacks such a headphone port.
The E-M10 IV is a recent model that features in the current product line-up of Olympus. In contrast, the A7S II has been discontinued (but can be found pre-owned on eBay). As a replacement in the same line of cameras, the A7S II was succeeded by the Sony A7S III. Further information on the two cameras (e.g. user guides, manuals), as well as related accessories, can be found on the official Olympus and Sony websites.
So how do things add up? Is the Olympus E-M10 IV better than the Sony A7S II or vice versa? The listing below highlights the relative strengths of the two models.
Arguments in favor of the Olympus OM-D E-M10 Mark IV:
- More detail: Offers more megapixels (20.2 vs 12MP) with a 27% higher linear resolution.
- Maximized detail: Lacks an anti-alias filter to exploit the sensor's full resolution potential.
- Fewer buttons to press: Is equipped with a touch-sensitive rear screen to facilitate handling.
- More selfie-friendly: Has an articulated screen that can be turned to be front-facing.
- Faster burst: Shoots at higher frequency (15 vs 5 flaps/sec) to capture the decisive moment.
- Easier time-lapse photography: Has an intervalometer built-in for low frequency shooting.
- More compact: Is smaller (122x84mm vs 127x96mm) and thus needs less room in the bag.
- Less heavy: Is lighter (by 244g or 39 percent) and hence easier to carry around.
- Easier fill-in: Is equipped with a small onboard flash to brighten deep shadow areas.
- Easier wireless transfer: Supports Bluetooth for image sharing without cables.
- Faster buffer clearing: Supports a more advanced SD data transfer standard (UHS-II vs UHS-I).
- More affordable: Was introduced into a lower priced category (77 percent cheaper at launch).
- More modern: Reflects 4 years and 10 months of technical progress since the A7S II launch.
Reasons to prefer the Sony Alpha 7S II:
- Better moiré control: Has an anti-alias filter to avoid artificial patterns to appear in images.
- Better sound: Can connect to an external microphone for higher quality sound recording.
- Better sound control: Has a headphone port that enables audio monitoring while recording.
- Larger viewfinder image: Features a viewfinder with a higher magnification (0.78x vs 0.62x).
- More detailed LCD: Has a higher resolution rear screen (1229k vs 1040k dots).
- Faster shutter: Has higher mechanical shutter speed (1/8000s vs 1/4000s) to freeze action.
- Better sealing: Is splash and dust sealed for shooting in inclement weather conditions.
- Easier device pairing: Supports NFC for fast wireless image transfer over short distances.
- More heavily discounted: Has been around for much longer (launched in September 2015).
If the count of individual advantages (bullet points above) is taken as a guide, the E-M10 IV is the clear winner of the match-up (13 : 9 points). However, the relative importance of the various individual camera aspects will vary according to personal preferences and needs, so that you might like to apply corresponding weights to the particular features before making a decision on a new camera. A professional wildlife photographer will view the differences between cameras in a way that diverges from the perspective of a family photog, and a person interested in architecture has distinct needs from a sports shooter. Hence, the decision which camera is best and worth buying is often a very personal one.
How about other alternatives? Do the specifications of the Olympus E-M10 IV and the Sony A7S II place the cameras among the top in their class? Find out in the latest Best Mirrorless Interchangeable Lens Camera listing whether the two cameras rank among the cream of the crop.
In any case, while the comparison of the spec-sheets of cameras can offer a general idea of their imaging potential, it says little about, for example, the shooting experience and imaging performance of the E-M10 IV and the A7S II in practical situations. User reviews that are available, for instance, at amazon can sometimes shed light on these issues, but such feedback is all too often partial, inconsistent, and inaccurate.
This is why expert reviews are important. The following table reports the overall ratings of the cameras as published by some of the major camera review sites (amateurphotographer [AP], cameralabs [CL], dpreview [DPR], ephotozine [EPZ], photographyblog [PB]). As can be seen, the professional reviewers agree in many cases on the quality of different cameras, but sometimes their assessments diverge, reinforcing the earlier point that a camera decision is often a very personal choice.
|1.||Olympus E-M10 IV||4.5/5||..||81/100||4.5/5||4.5/5||Aug 2020||699|
|2.||Sony A7S II||5/5||+||..||4.5/5||5/5||Sep 2015||2,999|
|3.||Olympus E-M5 III||5/5||+||82/100||4.5/5||4.5/5||Oct 2019||1,199|
|4.||Olympus E-PL10||..||..||77/100||..||4/5||Oct 2019||599|
|5.||Olympus E-PL9||..||+||..||4.5/5||4/5||Feb 2018||599|
|6.||Olympus E-M10 III||..||+||80/100||4.5/5||4.5/5||Aug 2017||649|
|7.||Olympus E-PL8||..||..||..||4.5/5||4/5||Sep 2016||549|
|8.||Olympus PEN-F||..||..||82/100||4.5/5||5/5||Jan 2016||1,199|
|9.||Olympus E-M10 II||4.5/5||+ +||80/100||5/5||5/5||Aug 2015||649|
|10.||Olympus E-M10||4/5||..||80/100||5/5||5/5||Jan 2014||699|
|11.||Olympus E-PL7||4/5||+||..||5/5||4/5||Aug 2014||599|
|12.||Panasonic G100||..||..||78/100||4/5||4/5||Jun 2020||649|
|13.||Sony A7S III||..||+ +||91/100||4.5/5||5/5||Jul 2020||3,499|
|14.||Sony A99 II||..||..||85/100||4.5/5||4.5/5||Sep 2016||3,199|
|15.||Sony A7R II||5/5||+ +||90/100||5/5||5/5||Jun 2015||3,199|
|16.||Sony A7 II||5/5||+||82/100||4.5/5||5/5||Nov 2014||1,999|
|17.||Sony A7S||4/5||..||86/100||4.5/5||5/5||Apr 2014||2,499|
|Notes: (+ +) highly recommended; (+) recommended; (o) reviewed; (..) not available.|
The above review scores should be interpreted with care, though. The ratings are only valid when referring to cameras in the same category and of the same age. A score, therefore, has to be seen in close connection to the price and market introduction time of the camera, and rating-comparisons among cameras that span long time periods or concern very differently equipped models make little sense. Also, please note that some of the review sites have changed their methodology and reporting over time.
Other camera comparisons
Did this review help to inform your camera decision process? In case you are interested in seeing how other cameras pair up, just make your choice using the following search menu. Alternatively, you can follow any of the listed hyperlinks for comparisons that others found interesting.
Specifications: Olympus E-M10 IV vs Sony A7S II
Below is a side-by-side comparison of the specs of the two cameras to facilitate a quick review of their differences and common features.
|Camera Model||Olympus E-M10 IV||Sony A7S II|
|Camera Type||Mirrorless system camera||Mirrorless system camera|
|Camera Lens||Micro Four Thirds lenses||Sony E mount lenses|
|Launch Date||August 2020||September 2015|
|Launch Price||USD 699||USD 2,999|
|Sensor Specs||Olympus E-M10 IV||Sony A7S II|
|Sensor Format||Four Thirds Sensor||Full Frame Sensor|
|Sensor Size||17.3 x 13.0 mm||35.6 x 23.8 mm|
|Sensor Area||224.9 mm2||847.28 mm2|
|Sensor Diagonal||21.6 mm||42.8 mm|
|Sensor Resolution||20.2 Megapixels||12 Megapixels|
|Image Resolution||5184 x 3888 pixels||4240 x 2832 pixels|
|Pixel Pitch||3.34 μm||8.40 μm|
|Pixel Density||8.96 MP/cm2||1.42 MP/cm2|
|Moiré control||no AA filter||Anti-Alias filter|
|Movie Capability||4K/30p Video||4K/30p Video|
|ISO Setting||200 - 25,600 ISO||100 - 102,400 ISO|
|ISO Boost||100 - 25,600 ISO||50 - 409,600 ISO|
|Image Processor||TruePic VIII||BIONZ X|
|DXO Sensor Quality (score)||..||85|
|DXO Color Depth (bits)||..||23.6|
|DXO Dynamic Range (EV)||..||13.3|
|DXO Low Light (ISO)||..||2993|
|Screen Specs||Olympus E-M10 IV||Sony A7S II|
|Viewfinder Type||Electronic viewfinder||Electronic viewfinder|
|Viewfinder Field of View||100%||100%|
|Viewfinder Resolution||2360k dots||2400k dots|
|LCD Framing||Live View||Live View|
|Rear LCD Size||3.0inch||3.0inch|
|LCD Resolution||1040k dots||1229k dots|
|LCD Attachment||Tilting screen||Tilting screen|
|Touch Input||Touchscreen||no Touchscreen|
|Shooting Specs||Olympus E-M10 IV||Sony A7S II|
|Focus System||Contrast-detect AF||Contrast-detect AF|
|Manual Focusing Aid||Focus Peaking||Focus Peaking|
|Max Shutter Speed (mechanical)||1/4000s||1/8000s|
|Continuous Shooting||15 shutter flaps/s||5 shutter flaps/s|
|Electronic Shutter||up to 1/16000s||YES|
|Time-Lapse Photography||Intervalometer built-in||no Intervalometer|
|Image Stabilization||In-body stabilization||In-body stabilization|
|Fill Flash||Built-in Flash||no On-Board Flash|
|Storage Medium||SDXC cards||MS or SDXC cards|
|Second Storage Option||Single card slot||Single card slot|
|UHS card support||UHS-II||UHS-I|
|Connectivity Specs||Olympus E-M10 IV||Sony A7S II|
|USB Connector||USB 2.0||USB 2.0|
|HDMI Port||micro HDMI||micro HDMI|
|Microphone Port||no MIC socket||External MIC port|
|Headphone Socket||no Headphone port||Headphone port|
|Wifi Support||Wifi built-in||Wifi built-in|
|Near-Field Communication||no NFC||NFC built-in|
|Bluetooth Support||Bluetooth built-in||no Bluetooth|
|Body Specs||Olympus E-M10 IV||Sony A7S II|
|Environmental Sealing||not weather sealed||Weathersealed body|
|Battery Life (CIPA)||360 shots per charge||370 shots per charge|
|In-Camera Charging||USB charging||USB charging|
122 x 84 x 49 mm
(4.8 x 3.3 x 1.9 in)
127 x 96 x 60 mm
(5.0 x 3.8 x 2.4 in)
|Camera Weight||383 g (13.5 oz)||627 g (22.1 oz)|
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